Canadian clinical trials of a vaccine against the pandemic H1N1 influenza will begin months after those trials are conducted in other countries but health officials in Ottawa say they will be completed by the time the vaccine is ready for production.
Spokesmen for GlaxoSmithKline, the pharmaceutical company licensed to produce the vaccine in this country, say they will have all “the information they need at the time that we actually have vaccine to immunize in November,” David Butler-Jones, Canada's chief medical officer of health, told a teleconference. “Hopefully, if all goes well,” he added.
Clinical trials of the vaccine have already started in Australia and are to begin in the United States in the near future. GlaxoSmithKline has said the Canadian trials will begin by September or early October.
Health Minister Leona Aglukkaq, meanwhile, has signed an interim order allowing doctors to prescribe the antiviral drug Tamiflu to prevent infection or treat cases of pandemic H1N1 in infants under one year old. Health authorities in the United States and Britain have made similar changes.
“The public health emergency created by the pandemic and this group's increased vulnerability from influenza created the urgent circumstances which deemed it necessary,” Ms. Aglukkaq said during the teleconference.
There are no antivirals authorized in Canada for treatment of such young children, and there are limited data on the use of Tamiflu for infants. But epidemiological data in Canada show this group is increasingly vulnerable to complications, including death, from the H1N1 virus.
Tamiflu and Relenza are effective in fighting H1N1, although there have been people who have shown resistance to the antiviral drugs. Most recently, a 60-year-old Quebec man was given Tamiflu after his son fell ill with the virus. He still got sick, becoming Canada's fist recorded case of Tamiflu-resistant H1N1 virus. The man recovered from the H1N1 flu without complications.
Dr. Butler-Jones assured parents that Tamiflu has a strong safety profile. The antiviral is not a cure for the flu, but a “strong and important” treatment option, he said.
“The effects of the influenza can be so severe, that it seems to me a fairly simple choice at that point,” Dr. Butler-Jones said yesterday. “The theoretical risk of a known drug that everything else has shown to be safe and effective compared to the very known risk of severe disease and the risk of dying from influenza, it seems to me a relatively easier choice.”
The decision to allow infants access to Tamiflu comes as the number of fatalities continues to climb. There were eight more deaths from the H1N1 virus in the past week, bringing the total number across Canada to at least 55.
The National Microbiology Lab in Winnipeg is beginning a study, with the help of intensive-care units across the country, to figure out why some people have been so severely affected, Ms. Aglukkaq said.
“The lessons learned from this study will help physicians, intensive-care and emergency-care specialists prepare for the anticipated wave of pandemic H1N1 in the fall,” she said.
Four provinces and 12 intensive-care units have already indicated that they will participate in the review of more than 100 cases of people who have been infected.
“We are reviewing the cases to determine what role, if any, factors such as age, weight, gender, underlying diseases, genetic background or immunization history play,” Dr. Butler-Jones said.
The study will look at which treatments work best, as well as the effectiveness of ventilation, blood pressure support and sedation.
Health officials are closely watching the virus as it circles the globe, particularly in the Southern Hemisphere, which is in the midst of its flu season. The virus is not yet mutating, a positive sign because a vaccine should be ready in the fall.
“We have not seen any significant changes in the virus since it was first recognized in late March or early April. We have sequenced novel H1N1 viruses from all over the world and they all are pretty consistent in regards to their genetic make-up,” a spokesman at the U.S. Centers for Disease Control and Prevention said Thursday.
